The reconstruction of the I-15 Virgin River Bridge No. 6 sets an award-winning example for efficient spending, time management, and teamwork
By Brianna Fries
Driving through the deserts and canyons of Arizona can be an awe-inspiring experience. That is, until you come across a bridge that looks like it wants to become one with the dust in the air around it.
For both local drivers and up to 1.4 million trucks that pass through Arizona, the structural integrity of the I-15 Virgin River Bridge No. 6 was something that they needed to count on. That is why the Arizona Department of Transportation (ADOT) reconstructed it and made it bigger and better than ever before. In fact, they did so well on this project that they earned the American Public Works Association 2017 Project of the Year award in the Transportation category.
As is the case with many bridges throughout the United States, the Virgin River Bridges are getting old. Virgin River Bridge No. 6 was originally built in the 1960s and was set to be reconstructed after it was declared structurally deficient with scour susceptible foundations, cracked steel girders that showed signs of fatigue, and almost no shoulders to speak of.
Reconstruction began in 2012 after the ADOT was awarded $21.6 million in TIGER Grant Funds. Immediately, the ADOT jumped into action to secure the funds and chose to utilize the construction manager at risk approach to do so, rather than the usual Design-Build process. Following the Construction Manager At Risk (CMAR) method allowed the ADOT to select a designer and contractor separately. The contractor was involved early on in the design process, which encouraged more manageable, predictive, and trustworthy relationships among the parties involved. The contractor was brought on board by early 2013 and final plans were completed less than a year later.
The key players for this project included the ADOT Bridges Group, the Joint Venture team for design, and Jacobs Engineering as the primary consultant, along with Pulice Construction and Wadsworth Brothers Construction as primary contractors. Adam Carreon of the ADOT pointed out, “Each group member had very specific traits that created a diverse group with a wealth of knowledge to quickly work through challenges as that arose.”
Techniques, Technology, and Special Considerations
The team working on the bridge utilized different techniques to ensure construction was safe, secure, and went on uninterrupted.
First, they installed a series of retaining panels, which kept environmental resources from falling into the river and provided workers with a solid, safe working area that avoided eroding, rutting, and SWPPP concerns. The panels also allowed them to create a temporary embankment adjacent to the river that was used as an access road to allow construction equipment to do work lower down in the canyon.
Second, the team installed a removable, temporary bridge over the Virgin River for construction access, which was designed to pass the 10-year flood underneath its girders. Should the river exceed the 10-year flow, the temporary bridge was designed to be lifted away in one piece by an on-site crane. This minimized its size and cost and mitigated the risk of the river flushing temporary structures downstream.
The project team also made sure to protect the surrounding environment during the reconstruction. There were sensitive species and critical habitats for endangered species near where the project was located. The project team was kept informed of these details to make sure they provided protection to these species and didn’t disturb them or harm their habitats.
An Inspiring Success
The reconstruction of the I-15 Virgin River Bridge No. 6 was a success. Both the public and the Department of Public Safety liked the expanded width of the bridge and increased shoulder, allowing cars to pull off to the side of the road safely in an emergency. This project also made a great example for future projectsby efficiently using the funds it was granted by the TIGER Grant, the State of Arizona, and the FHWA.
“The project was completed on time and under budget,” explained Carreon. “The dedication to partnering from the start was why this project was so successful and is the reason we won the APWA Project of the Year along with many other awards.”
The reconstruction of the Virgin River Bridge No. 6 is just the first step in a much larger project. Bridge No. 6 is one of eight I-15 bridges that were built over the Virgin River in the 1960s, and most of them are in need of repair. “The bridges on I-15 in Arizona are reaching the end of their life span and will all eventually need to be replaced,” Carreon confirmed. “The bridges are regularly inspected so the ADOT can accurately plan the order of construction. Virgin River Bridge No. 1, which is the only bridge outside of the gorge, is scheduled to be replaced next.”
Brianna Fries is an Assistant Editor for American Infrastructure Magazine. She can be reached at firstname.lastname@example.org